The incidence of lung carcinoma after surgery for breast carcinoma with and without postoperative radiotherapy

Abstract

BACKGROUND In the current study, the authors compared the incidence of subsequent primary lung carcinoma in patients with breast carcinoma who received radiotherapy as part of their treatment and in those patients who did not. The patients were participants in two large National Surgical Adjuvant Breast and Bowel Project (NSABP) breast carcinoma trials, B‐04 and B‐06, which prospectively randomized women to either undergo surgery alone or to undergo surgery and postoperative radiotherapy. METHODS The NSABP trial B‐04 (1971–1974) randomized patients to undergo radical mastectomy versus total (simple) mastectomy and radiotherapy to the chest wall, axilla, and supraclavicular and internal mammary lymph node areas. For patients with a clinically uninvolved axilla, there was a third randomization arm: total mastectomy without radiotherapy. The B‐06 trial (1976–1984) randomized patients between those undergoing total mastectomy versus lumpectomy versus those undergoing lumpectomy and breast irradiation, with all patients undergoing an axillary lymph node dissection. The records of all patients who developed a recurrence in the lung or a new primary lung tumor were reviewed to determine the incidence and laterality of confirmed and probable primary lung carcinoma. RESULTS For the 1665 evaluable patients on the NSABP B‐04 trial (mean follow‐up of 21.4 years), there was a total of 23 subsequent confirmed and probable ipsilateral or contralateral primary lung carcinomas. In those patients who had received comprehensive postmastectomy radiotherapy, there was a statistically significant increase in the incidence of these new primary tumors (P = 0.029). With regard to the development of confirmed new primary ipsilateral lung carcinoma alone, the incidence was statistically significantly increased (P = 0.013) in those patients who had received radiotherapy as part of their treatment, and when confirmed and probable ipsilateral lung carcinomas were analyzed, there was a strong trend toward a statistically significant increase in those patients who had received radiotherapy (P = 0.066). For the 1850 evaluable patients on the NSABP trial B‐06 (mean follow‐up of 19.0 years), there was a total of 30 second primary lung carcinomas but no increase in either ipsilateral or contralateral primary tumors of the lung in those patients who had received radiotherapy. CONCLUSIONS Extensive postmastectomy irradiation of the chest wall and regional lymphatic node areas, with consequent exposure of a greater volume of lung to higher doses as administered in the NSABP B‐04 trial compared with postlumpectomy breast irradiation in the NSABP B‐06 trial, was associated with an increased incidence of subsequent primary lung tumors, both ipsilateral and contralateral. Cancer 2003;98:1362–8. © 2003 American Cancer Society. DOI 10.1002/cncr.11655